After losing much of her hair to chemotherapy treatment, Kate Pepper said the turquoise-toned wig she'd found made her feel "awesome."

That was way better than the 17-year-old McKinney High senior had felt lately, having been re-diagnosed two months ago with a form of brain cancer called anaplastic astrocytoma.

But this week, as KXAS-TV (NBC5) reported, McKinney ISD officials informed Kate that the wig she'd found just a week before school started violated district dress code and wouldn't be allowed on campus.

"I honestly just wanted to cry," she told the news station.

Kate had first been diagnosed with cancer four years ago. She thought she had it beat, but when she wasn't feeling herself earlier this year, she learned that the malignant tumor was back.

"I was feeling bad, but I wasn't expecting it to be brain cancer again," she said.

As treatment for the disease caused her hair to fall out, she went shopping for a wig and found the turquoise-tinted one she says changed her outlook.

"I got super excited when I put it on," she said. "I felt awesome."

A close-up of Kate's turquoise wig from a video interview with NBC5.

(/KXAS-TV (NBC5))

But the wig didn't conform to district code, which specifies that "Non-natural colored hair that is considered to be disruptive (green, blue, purple, orange, etc.) is not permitted."

Kate's mom, Tyliese Pepper, wrote to the school and to district officials, hoping to change their minds. The reply stated that the district was unable "to grant the ability to wear a wig with turquoise in it."

While a McKinney High staff member did offer Kate money to pay for a new wig, it's really not about the money, her mom said.

"It's about the principle of you letting her wear the wig," Tyliese Pepper said. "She's fighting for her life. Why do we have to fight for this?"

A district spokesperson said that while officials' hearts go out to families enduring such difficult circumstances, "we must also remain consistent in our implementation of the student handbook, including the student dress code."